During the manufacture of fan, turbine and compressor blades of a gas turbine engine, it is necessary to machine it to exact specifications. In order to effect this machining, the blades have to be held in position. This is currently carried out by tooling which clamps the aerodynamic surfaces of the blades to deform them to the shape of the tool. When the tooling releases the blade, it springs back to its original shape. This can be disadvantageous, because each blade requires its own special tool, and when the blades spring back to their original shape, this can change the position of machine features relative to the blades datum.